Blue-printing machine



Octg 1s, 1927.

1,646,331 F. J. TRUMPOUR BLUE PRINTING MACHINE Filed July 2l. 1926 5 Sheecs-Shee'c 1 Oct. 18, 1927.

1,646,331 F. J. TRUMPOUR BLUE PRINTING MACHINE- Filed July 2l, 1926 5 Sheets-Sheet 2A SW1/bof?, J Trulli/Daw F..J. TRUMPOUR'v BLUE PRINT'INGjMACgINE Filed July 2l. 1926 5 Sheets-Sheet V3 Oct 1.8i) F. J. TRUMPOUR .BLUE PRINTING MACHINE 5 Sheets-Sheet 4 Filed July 21. 1926 l l 1 646 3 l Oct 18, 1927. F, J. TRUMPOUR l 3 BLUE PRISJTING MACHINE Filed July 2l, 1926 5 Sheets-Sheet 5 Figo? aww/Iwo@ J Tram/poul' .Z5 ZIZM fr www.

Patented Oct. 18, 1927. j

UNITED STATES FREDERICK JAMES TRUMPOU'R,

F FOREST GLEN, MARYLAND.

BLun-PniNTING MACHINE.

Application filed J'u'ly 21,

The present invention relates to improvements in blue-printing machines and has for an object to provide an improved machine. which will provide for the printing upon both sides of the sensitized blue-printpaper in one passage of the paper through the machine.

Another object of the invention resides in providing a simple, compact and inexpensive machine, wherein this duplex printing upon both sides of the blue-print paper may be carried on cheaply and expeditiously.

The invention also contemplates the use of the machine for single printing upon onev side only of the blue-print pape-r.

1With the foregoing and other objects 1n View, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto. v

In thev drawings, wherein like symbols refer to like or corresponding parts throughout the several views,

Fig. 1 is a side elevation of an improved blue-printing machine constructed according to the present invention.

Fig. 2 is a vertical section taken on the line 2-2 in Fig. 1.

Fig. 3 is also a vertical section taken on the line 3-3 in Fig. 2.u

Fig. 4 is a fragmentary horizontal section taken on an enlarged scale throughthe feeding apparatus.

Fig. 5 is a vertical section through the same apparatus on the line 5-5 in Fig. 4.

Fig. 6 is a vertical section taken on the line 6-6 in Fig. 5.

Fig. 7 is an enlarged fragmentary section taken through a portion of the tracing clamping device. Fig. 8 is a similar/view .taken along the line 8-8 in Fig. 7.

Fig. 9 is across-section taken on the line 23T-9 in Fig. 8, with the clamp mechanism 1n the closed position.

Fig. 10 is a similar view showing the j clamp open; and

Fig. 11 isa fragmentary section taken on the line 11--11 in Fig. 5, showing registering bars engaged with means for releasing the tracings.

Figure' 12 is an enlarged sectional view of one of the socket members showing the spring. i

Referring more particularly to the drawings, 12V designates generally the framework 1926. serial No. 124,046.

of the machine, which framework may be of metal oil any appropriate material shaped and constructed to carry the two exposure stations and the apparatus for feeding the sensitized blue-print paper and the two negatives or tracings past such stations.

The movement for passing the blue-print paper and negatives through the machine is derived from any appropriate source' for instance, from the electric motor 13 s own as installed in the base of the frame 12. The motor shaft 14 may be provided with the worm 15 meshing with the worm wheel 16. In Fig. 3 this worm wheel is shown as mounted fast upon a transverse shaft 17 journaled in appropriate bearings in the framework and having thereon also the beveled pinion 18 disposed in mesh with a similar pinion 19 upon the Vertical transmission shaft 20. This shaft 20 extends 11p along one side of the framework and is procommunicating motion to the various feed and transmission belts as hereinafter described.

In Fig. 2 is shown as extendin from one side of the frame an assembly ta le 21 carried upon an extension frame 22 which alsd supports theA sprockets 23 and 24 for the pair of upper feed chains 25; and the other pair of `sprockets 26 and 27 for the pair of lower feed chains 28. The adjacent runs of these feed chains pass above the assembly table 21 and these feed chains each carry a negative or tracing clamp bar to which an end of each tracing is secured for the purpose of initially ldrawing the tracing into the machine. At the inner end of the assembly table 21 is placed a casing 29 for containing the roll 30 of blue-print paper containe upon the shaft 31 from which it is unwound and passed outwardly through the slot 32. The adjacent runs of the upper and lower feed chains are adapted to pass respectively above and below this casing 29 and the upper run of the lower feed chain is re uired to pass through a trough made by the ower portion of the cylindrical casing 29 and an apron 33 extending from the inner end of the assembly table 21 and adjacent to the curved feed or contact table 34.

The blue-print paper is drawn `out through the slot 32, as shown in Fig. y5, and in between the tracings or negatives conveyed along by the clamping device on the upper and lower feed chains. The three supervided with appropriate beveled gearing for posed films or webs are pressed tightly against the contact or feed table 34 and are advanced along such table 34 by means of upper and lower feed belts 35 and 36, the adjacent runs of which pass above the curved contact table 34, in contact with'each other and with the curved table. These feed belts 35 and 36 are narrower than the space between the pairs of feed chains, as lndicated in Fig. 4, in order to allow ample space at the sides of the feed belts for the placement of adjacent mechanisms. The upper feed belt 35 is carried upon the rollers 37 and 38;v while the lower feed belt 36 isltrained over similar rollers 39 and 40. The lower roll-` ers 39 and 40 are mounted in the iixed spindles or shafts 41v and 42 journaled. 1n-the side plates 43 of the framework wh1le the upper rollers 37 and 38 are mounted upon the shafts 44 and 45 extending through the slots 46 in the side plates 43, such slots extending vertically whereby the upper rollers 37 and 38 may be lifted away from the respective rollers 39 and 40 of the lower feed mechanism. This separating movement of the several rolls and. the belts is necessary to permit the clamping bars carrying the tracings or negatives past such feed mechanism. In order to accomplish the lifting .of the outer feeding roller 38,v a pair of dogs 47 having wedge or cam upper surfaces disposed lbeneath the shaft 45 are provided, such dogs being pivotally hung upon the rod 48. The dogs are in position to be engaged as to their under edges by the clamp bars as they pass downwardlyrtoward the feed belts. In Fig. 2 'the dogs land the roller 38 are shown in the lower position; while in Fig. 5 the parts are shown in the raised position without clamp bars between the rollers 38 and 40.

These clamp bars are shown more particularly in Figs. 7 to, 10, inclusive, and they are formed with the central cores 49 and outer shells or casings 50. Both the cores and shells are formed with complementary depressions and crests 51 and 52 'preferably on the under sides thereof and these cores and shells are shiftable axially whereby to cause the depressed portions of the shell to ride outwardly on the crests of the bars. This causes the clamp jaws 53 and 54 to open as shown in Fig. 10. When the parts are restored to the positions shown in Fi 8 and 9, wherein the depressions of the shells or casings lie in the depressions of the bars, the clamp `jaws 53 and 54 are closed. The end or other portion of a negative or a tracing is adapted to be clamped by the jaws 53 and 54, the jaws being initially opened by the method above described for receiving same; The opening of the jaws may be either automatic or by hand, but provision for automatically opening the jaws at a later stage in the machine must be provided for and to this end the casing or shell 50, which casing extends completely across the space between the rollers 38 and 40 is made stationary While the cor-es are movable axially therein. There are two 'cores in each shell, separated by the space collar 57 is a head 55 provided with a reduced portion 59 for fitting within and closing the outer end of the casing or shell 50. The head and casing`are made fast. It is understood that the same type of head is provided to close the opposite end'of the casing or shell.

The two cores within each ofthe shells. are provided with outer terminal squared portions 60 adapted to fit into sockets 61 carried by the feed chains 25 and 28. These sockets project laterally and inwardly from the chains and it is preferred to supply each link of the chain with such a socket in order that the clamp bars may be selectively attached at any desired point along the chain. The sockets 61 are provided with three walls (Figs. 5 and l2) for engaging three sides of the squared terminal end 60 of the core but one side of the socket is left open to receive such lterminal end 60 and in order to maintain the terminal end in the socket,

a flat spring 62 -is secured as by the set screws 62 to one side of the socket and has its free ends overlapping the yopen side of the socket and preferably flared outwardly as at 300, Fig. 12, in order to admit of prying apart to admit the terminal end 60. These free ends of the spring yieldably re-y tain the terminal ends 60 in the socket. The terminal .end 60 of the core is adapted to slide axially in the socket and lto be normally held projected by the coil spring 63 which is fitted in the innermost portion of the socket. The socket end is closed by the screw plug 64 by means of which access may be had to the socket for removing the spring. The other end of the spring is adapted to receive the pin 65 for abutting directly against the end of the core terminal 60. The socket may be constituted of one of the pin connections of the chain link or it may be another portion of the chain as desired.

Referring to Fig. 4, it will be apparent that the set collar 57 is provided with a forj wardly inclined curved or cam nose 66 posi-v tioned to engage with the forwardly inclined or cam edge 67 of an abutment or cam wall 68 mounted ateach end of the inner feed rollers 37 and 39. As shown in Fig. 11 the cam or abutment plate 68 is the sprockets 23 and 26. The

tension frame by means of the web 69 extending horizontally from the wall 43. The

vwall'4-3 is also' provided with the spaced horizontally extending guides 7 O and 71 for receiving the chain links and for guiding the chain in its movements. The abutment plate 68 is provided upon its inner side with 'a fiat abutment surface 72 for receiving the outer end of the head of the casingor shell for the clamp bar in order to hold the casing against movement while the core within is shifted axially by reason of the engagement of the .cam set collar 57 with the inclined ment wall. When the set collar 57 is behind the abutment or cam wall, the pressed portions of the core have been moved over against the inner depressed portions of the shell and consequently the clamp jaws 53 and'54, which have been lately holding the tracings or negatives are opened and thetracings or negatives are released. 'l his operation is essential as the clamp bars and shell turn about the sprockets 23 and 26 and return in the opposite direction upon thelrouter runs of the feed chains; while the blue-print paper and superposed and underlaid tracings are required to pass on to the first exposure station.

The abutment Wall 68, as shown in Fig. 5, is also provided with the divergent iaring ends 73 and 74 for the purpose of deecting the clamp bars in opposite directions about lower clamp I bar is designed to'strike a cam lever 75 as -about i it passes about the sprocket 26, the arm of such cam lever extending across this path of movement and the lever being fulcrumed as indicated at 76 on an appropriate support. .The lever will therefore be swung in a counterclockwise direction. This same movement causes a pull to the left to be exerted upon the rod 77 provided at one end to the cam lever and at its other end to the arm 78 upon the sliding feed plate 79 having one end arranged above the contact or feed table 34 and which plate 79 extends between the feed belts 35 and 36' and resting upon the latter, Vbetween the rollers 37 and 39. A coil spring 8O is attached to a fixed part and to the arm 78 for normally holding the feed plate 79 in the normal position shown in Fig. 5. The inner edge of this feed plate is adapted to stop short of the rotary path that the clamp bar is Arequired to. take in passing about the lower sprocket 26, but as soon as this clamp bar has passed through the gap provided by the end of this feed plate 79, the clamp .bar strikes the lever 75 and causes consequent shifting of the plate 79 inwardly to close the gap between this saine plate 79 and the bridging plate 81 disposed between the feeding apparatus and the belt 82 which extends sage of the clam surface 67 ofthe cam or abut- 'posed above the feeding apparatus.

about the first blue-printing or exposure station. It will be understood that the feed plate 79 is narrower in width than the distance between the pair of abutment or cam Walls 68 and consequently these cam walls Will not interfere with the backward and forward shifting movement of the plate 79 4as just described. The upper clamp bar,

passing along beneath the lower run of the upperfeed belt 35, will, as it approaches the roller 37, lift this roller to permit pasbar between the rollers 37 and 39 permitting the clamp bar to move on its way up about the sprocket 23.

A` yoke 83 is provided in conjunction with the feeding` apparatus, such yoke adapted to have a vertical sliding movement given it through the link 84 and the lever handle 85 fulcruined upon an appropriate part of the framework. The yoke arms 86 and 87 engage below the arms 88 and 89 which are pivoted at the central point 90. These arms are coupled to the shafts 44 and 45. of the upper belt rollers. By depressing the lever arm 85, as shown in Fig. 2, the yoke is lifted and with it the yoke arms and the arms 88 and 89. rl`he rollers 37 and 38 and the upper feed belt 35 is thereby lifted. A flat bow'spring 91 is provided to bear upon the arms 88 and 89 for the purpose of keepf ing the rollers 37 and 38 down and to maintain or increase the pressure between the upper and lower belts, and over the curved contact table 34 with the contained moving print paper and tracings or negatives.

l'llhe belt 82 which receives the blue-print paper and negatives from the feeding apparatus extends about the end rollers 92and 93 and the intermediate roller 94. The roller 92 is disposed beneath the bridging plate 81 and the belt 8 2 is made to assume a curvature about the glass convex exposure plate 95 within which are situated one or inorefirst exposure and to carry this tracing or negative ofil and into the hopper 99 disblue-print paper, which has been previously threaded entirely through the machine as indicated in-dotted lines atl 100 then maintains the innermost negative or tracing in contact with the belt 82 and the two are driven up to the transposed or inverting device, which device includes the curved contact table 101 iso and the upper and lower belts 102 and 103. The upper belt extends about the end roll ers 104 and 105, and about the intermediate roller 106 while the lower belt extends about the rollers 107 and 108. The adjacent runs of both belts extend above and in contact with the convex or curved. table 101 and the remaining tracing or negative and blue- .print-paper are intended to be received between the adjacent runs of such belts, the belts being driven as hereinafter explained, to feed the blue-print paper and tracing to the second or finalv exposure station. The Contact table 101 and the belts 102 and 103 are all carried by a unit frame 109l pivoted about the center 110 which is the axis of the roller 93. This enables the frame 109 carrying all of the parts referred to to be swung outwardly as when cleaning curved. exposing glass or the lamps. Pivoted directing plates 111 and 112 are placed. at opposite ends of the transposing or inverting apparatus in order to bridge the gaps necessarily left between the bights of the rollers and to conduct the films or webs from one roll to another. The upper exposure station consists of the convex glass exposure plate 113 which is carried in the main frame above the first exposure station and its convexity extends in an opposite direction to the convexity of the first glass exposure plate 95. Behind the'plate 113 are the lamps 114 and a belt 115 is used to feed the tracing and sensitized paper and to create pressure of the two against the plate 113. The belt 115 extends about the rollers 116 and 117 at the ends of the belt and about the intermediate roller 118. The second tracing or negative is carried .off by an apron 119 and its lip 120 to a second hopper 121 disposed at the opposite-side of the framework from the first-mentioned hopper. The blue-print paper indicated by the dotted line 100 is carried upwardly and over the rolls 122 and 123 carried upon suitable' arms or brackets at the top of the machine; the blueprint paper being subsequently conveyed to a washing and drying apparatus.

Now the various rolls for the belts may be driven in any appropriate manner; for 1nstance, by means of the arrangement of the gearing shown. which is all taken'of from the shaft 20. This shaft 20 is provided with a beveled pinion 124 shown in Flg 1 for meshing with a second beveled pinion 125 on a horizontal shaft 110. This shaft 110 1s the shaft for the roll 93 and this'roll and the belt 82 is drivenl through this train of connection.' Power is also taken off from the shaft 20 by means of the beveled-gear wheel 126 meshing with the companion gear I wheel 127 on the horizontal shaft 128 which extends over the opposite side of the. frame and is provided vwith the beveled pinion 129 disposed in mesh with the `s1m1lar compa-nion pinion 130 on the vertical rod or shaft 131 which parallels the shaft 20. As shown in Fig 3 the shaft 131 at its upper end is provided with the pinion 132 arranged in mesh with the companion pinion 133 on the horizontal shaft 134 of the roll 117. This arrangement provides for driving the upper belt 115. The shaft 131 extends down to the feeding apparatus as shown more particularly in Fig. 4 where it is provided with the beveled pinion 135 meshing with the opposite pinions 136 and 137 and with the right--angularly disposed pinion 138 on the shaft 139 by which power is comi'nunicated through the beveled gear wheels -140 and 141 to the shaft45 of the feed roll 38. The beveled gear wheel 137 is mounted on the stub shaft 90 having also the sprocket 142 over which extends the chain 143 indicated in Fig 5 by which power is conveyed to a lower sprocket wheel 144 on a shaft r 145 which also drives the chain 146 whereby motion is communicated to the shaft 42 of the roll 40 for the lower feed belt.

Power is also taken 0E from the shaft 145 to drive the chain 147 which extends to a smaller sprocket on the shaft 26 to the lower feed chain\ whereby said lower feed chain is driven.

The pinion 136 shown inl Fig. 4 is mounted on a stub shaft with a sprocket 148 for driving a chain 149 which also extends about a sprocket on a shaft 151 of the roller 23 for the upper feed chain. It is thus noted that the feed chains will be driven in opposite directions as required.

The transposing and inverting belts are driven from the shaft 11,0 of the roll 93 by means shown in Fig. 1. The shaft 110 and the shaft 152 are provided with sprockets to receive the chain 153 and shaft 152 is extended and provided with av pinion 154 meshing with another pinion 155 on the shaft 156 of the roll 107. Thereby both belts 102 and 103 are driven by power derived from shaft 110.

In operation, blue-print paper, having an emulsion upon bot-h sides'and contained in a roll is mounted within the casing 29 in the feed apparatus. This blue-print paper is attached with paste to a leaderstrip which is initially threaded through the entire machine and is brought out as shown'by the dotted line 100 in Fig. 2. In order to get atv this leader strip, the leve-r shown in Fig. 2 may be depressed to raise the upper feed rollers and belt and enable the leader strip to be brought across through the feeding apparatus up to and engaged with the belt 82. After the leader strip is'properly threaded through the machine, and the attached print paper is in motion through the contact table 34, the two tracings or negatives, which have been previously secured in the clamp bars by `opening the jaws 53 and 54, are attached to the moving chains to register one above iop of the blue-print paper. Consequently, when machine and delivered to the hopper 99 whilef these three superposed webs or films arrive o posite the first exposure station, the upper slde of the blue-print paper will be printed from the uppermost negative or tracing. This tracing is thereafter removed from the the blue-print paper and tracing that was initially lowermost is passed on upwardly and made to undergo a transposing or, inverting movementI by which the initially lowermost tracing or negative is brought uppermost and against the convex glass plate 113 at the upper exposure station thus bringing the parts into position for printing upon the opposite side of the blue-print paper of the matter on the second tracing. The second tracing is then delivered to the upper hopper 121 and the blue-print paper carried 0E -as sho-wn in dotted lines in Fig. 2 of the washing and drying stations.

As the registering bars return to the front of the assembly table they are automatically released by means ofthe stops 203 and 204 and drop into the hoppers 205 and 206.

If it is desirable to print a single sheet upon both sides, the leader strip'is not fed through the machine, but a sheet of the sensitized double coated paper is cut olf of the requiredv size; the two tracings are attached to the registering bars and' the sheet of cut paper attached to the power registering bar and on top of the tracings in which position the bars are attached to the chains which will advance them to the various positions, as above described, for the printing of the two tracings, one on either side of the paper..

For printing on one side of a continuous roll the fram-e 22 is lowered by means of the rack 200 and inion 201 to such position that a board, not s own, may be placed across the frame 22 allowing tl paper with its superimposed tracing to be fed direct to the belt 82.

From the' above description it will be seen that by the use of these improvements a 100% 'utilization of the surface'of the print paper is made when printing on both sides of such paper; that a continuous roll or sin- `gle sheets maybe printed; that a double or single printing maybe accomplished; that it requires only one operator, and in the case of the double printing the product al'- lows a large saving in the amount of paper used, storage space required for record prints, reduced cost in transportation, as

well as other advantages.

The machine may be also used by inserting two single coated rolls with the uncoated surfaces in contact and then feeding the tracings as before which will increase the capacity of the present method of getting single coated blue prints 100%.

It will be obvious also that many other 'changes in the construction, combination and 1 arrangement of parts could be made, which could be used without departing from the spirit of my invention, and I do not mean to limit the invention to such details, except as particularly pointed out in the claims.

Having thus described my invention, what I claim and desire to secure by Letters Patv'ent of the United States is:

1. A blue printing machine comprising an assembly and feeding station for initially assembling two tracings and asheet of blue print paper sensitized on both sides with the tracings on opposite sides of the blue print paper, an initial exposure station past whichthe two negatives and blue print paper are moved together for printing one side of the 'nsv blue print paper from one ofthe tracings,

.and a second exposure station for receiving the blue printv paper and other tracing for printing upon the opposite side of the blue print paper the contents of the second tracing.

2. A blue rinting machine comprising an assembly and feeding station for disposing a negative upon each side of al sensitized blue print paper having an emulsion upon both sides thereof, an initial exposure station for receiving said superposed negatives and blue print paper and for 'exposing' one side of the blue print paper to one of the negatives, means for subsequently carrying off the printed negative, and a second exposure station for exposing the opposite side of the blue print paper to the second negative.

3. A blue printing machine comprising an negatives, means for subsequentlybarrying 0E the printed negative, and a second exposure station for exposing the opposite side of the blue print paper to the second negative, means for conveying of the second negative from the second exposurestation, and means for conveying 0E vthe doubly exposed blue print paper separately;

4. A blue rinting machine comprising an assembly and) feeding station for introducing negatives in matching relation atopposite sides of. a blue print paper having both sides sensitized, an' initial exposure station for printing one side of the blue print paper j from one of the negatives, a holder for receiving the printed negative after passing through saidi'nitial'exposure station, a translposing and inverting vdevice for receiving a holder for receiving said printed tracings after passing through the initial station, a transposing and inverting device for receiving the blue print paper and other tracing from the first station, a second exposure station for receivingthe blue print paper and other tracing from the transposing and inverting device, whereby Ato print the blue print paper upon the opposite side, a holder for receiving the other tracing after passing through the second station, and means for separatelycarrying oi the blue printpaper.

6. A machine for making blue prints from tracings comprising a narrow vertical frame, exposure stations mounted one above another in said frame, a transposing and inverting.-

device between said stations, receptacles at opposite sides of said stations for receiving the previously `exposed tracings, means at the upper portion of theframe for carrying oli' the blue print paper separately from the tracings, a feeding mechamsm, .and an as sembly mechanism for superposing the tracings upon opposite sides of the blue print paper;

7. A blue printing machine comprising a main frame, an initial exposure station on said frame having a convex plate, a source of illumination behind the plate, and a feed `belt adapted to move over said plate, a second exposure station on the main frame above the initial station and composed also of a convex plate, an illuminating source behind the plate and a moving belt extending across the plate, said plate extendingoppositely to the rst mentioned plate, means for feeding to the initial plate and belt, a sheet of blue print paper with a tracing above and below the same, whereby to expose one side of the blue print paper Lto the respective tracing, means for carrying olf the exposed tracing, means for inverting the blue print paper and second tracing and for delivering samevto the second exposure plate and belt,

and means: for separating the second tracing and blue print paper after the second exposure.

8. A blue printing machine comprising a frame,.an .initial exposurestation on vsaid frame, a final exposure station on the frame above the initial station, means for feeding to the initial station a blue print paper with tracings on opposite sides of same, means for removing beyond the initial station the printed tracing, an inverting device for receiving the other tracing and blue print paper from the initialstation and passing the same -to the final station, said inverting device. comprising a curved pressure plate and belts having their adjacent runs on the convex side of said plate and'being stretched tightly across said plate, the tracing and blue print paper adapted to be received between the adjacent runs of said belts.

9. A blue printing machine comprising a frame, an initial exposure1 station on said frame, a final exposure station on the frame above the initial station, means -for feeding to the initial station a blue print paper with tracings on opposite sides of same, means.

for removing after the initial stationl` the printed tracing, an 4inverting devicefor receiving the other tracing and blue print paper from the initial station and passing same to. the final station, said inverting device comprising a convex pressure plate and belts moving in the same direction over the convex side of said plate and a hinged frame' carrying` said plate and belts and adapted to swing outwardly to deliver the blue print paper and tracing ata remote point from the final exposure station.

.10. A blue printing machine comprising,v

an exposure station, and means for feeding a blue print and tracing to the exposure station comprising an assembly table, means for Amoving the tracing over said table, means for holding a blue print paper to be placed alongside said tracing, and feeding means in advance ofthe exposure station for pressing and advancing said superposed tracing and blue print paper.

11. A blue printing` machine comprisingV an exposure station, and means for assembling and feeding` a superposed tracing and blue print paper to the station comprising f a movable chain, means attachable to the chain for clamping and drawing the tracing therealong, means for holdin the blue printv paper adjoining the chain, w ereby the blue print paper may be drawn out against the tracing and pressure and feeding means for pressingthe blue print paper and tracing tightly together and' advancing same ,to the exposure station.,

12. A blue printing machine comprising an exposure station, pressure feeding belts adjoining 'said station, means for moving said belts, a blue print roll adjoining the` belts and'means for drawing two tracings in opposite directions about said blueprint roll and upon opposite sides of the blue print paper issuing` from said roll.

13. A blue printing machine comprising vcurvedl pressure' plate bearing against said adjacent runs of the belt for placing them under tension, a blue print roll adjacent the belts, and movable means for drawing two 'tracings along and upon opposite sides of said blue print roll andfor drawing the tracings through the belts on opposite sides of theblue print paper issuing from said roll, and means for, detaching the tracings from said last named means.

' 14. A blue printing machine comprising an exposure station, a pair of feeding belts adjoining said station, a blue print roll adjoining the .feeding belts, .endless driven chains, means carried by `said chains for drawing two tracings. in the same'direction labout the blue print roll and through said feeding belts upon opposite sides of the blue print paper, while the belts subject the tracings and paper to pressure for feeding thel blueprint paper along, and means forl disengaging said last named means.

l5. A blue printingmachine comprising an exposure station, pressure and feeding belts adjoining said station, a blue print roll adjoining the belts, endless driven chains extending about said roll and about said feeding belts, clamp bars removablyl attached to saidchains for grasping and drawing tracings along with the chains and to opposite sides ofthe blue print paper and through'said feeding. belts, and means for automatically disengaging the tracings from said clamp bars. j

16. A blue printing machine comprising an exposure station, 4pressure means adjacent the station, tracing feeding means, a blueprint roll extending between said tracing feeding means, said tracing feeding meansy including clamp .bars composed of openable jaws for grasping the tracings'and relatively movable parts for opening and closing said jaws, and means for automatically opening said jaws when the tracings have arrived adjacent the exposure station.

17. A blue printing machine comprising an exposure station, pressure means adjoining the station, tracing feeding means, a blue print roll betweenl said tracing feeding means adjoining said pressure means, clamp bars removably carried by said tracing feeding means and having spring jaws for receiving the tracings, said bars being composed of inner movable cores and outer relatively fixed shells,isaid cores and shells having troughs and crests arranged therebetween for opening and closing the jaws on axial shifting 'movement of the cores and means for automatically shifting said cores.

18. A blue printing machine comprising an exposure station, a blue print roll, endless chains upon opposite sides of said roll and having sockets therein, clamp bars adapted to be selectively attached to said chains and composed of outer resilient shells and inner axially movable cores having the ends detachably fitted in said sockets, clamp collars on said cores, fixed cam abutments for engaging said collars to shift said cores and for holding said. shells against movement, and resilient means tohold said cores in initial position.

19. A blue printing machine comprising anl exposure station, a pair of feeding belts adjoining the station for receiving tracings and blue printi paper, a curved contact table forbearing upon the adjacent runs of the belts, means for positively drawing the tracings through the belts, a movable late near the deliver end of said belts, resi ient FREDERICK JAMES TEUMPOUR. 

